Although scientists are uncertain whether climate change will lead to an increase in the number of hurricanes, warmer ocean temperatures and higher sea levels are expected to intensify their impacts.
Recent analyses conclude that the strongest hurricanes occurring in some regions including the North Atlantic have increased in intensity over the past two to three decades. For the continental United States in the Atlantic Basin, models project a 45-87 percent increase in the frequency of Category 4 and 5 hurricanes despite a possible decrease in the frequency of storms.
Hurricanes are subject to various climate change-related influences:
Warmer sea surface temperatures could intensify tropical storm wind speeds, potentially delivering more damage if they make landfall. Based on sophisticated computer modeling, scientists expect a 2-11 percent increase in average maximum wind speed, with more occurrences of the most intense storms. Warmer seas also mean more precipitation. Rainfall rates during these storms are projected to increase by about 20 percent and, as Hurricane Harvey showed in 2017, this can sometimes be the more destructive impact.
Sea level rise is likely to make future coastal storms, including hurricanes, more damaging. Globally averaged, sea level is expected to rise by 1-4 feet during the next century, which will amplify coastal storm surge. For example, sea level rise intensified the impact of Hurricane Sandy, which caused an estimated $65 billion in damages in New York, New Jersey, and Connecticut in 2012. Much of this damage was related to coastal flooding.
The connection between climate change and hurricane frequency is less straightforward.
Globally, about 70 to 110 tropical storms form each year, with about 40 to 60 reaching hurricane strength. But records show large year-to-year changes in the number and intensity of these storms.